Researchers looked at 32 patients, aged 8 to 19, who had suffered a moderate to severe brain injury in the previous five months. The kids underwent tests to assess how fast they could process and recall information. The researchers also recorded electrical activity in the patients' brains to determine how quickly their brain nerve fibers could transmit information. And imaging scans assessed the structural condition of the youngsters' brain wiring.
"Just as electricians insulate electrical wires to shield their connections, the brain's nerve fibers are encased in a fatty tissue called myelin that protects signals as they travel across the brain," Dr. Christopher Giza, a professor of pediatrics and neurosurgery at the University of California, Los Angeles, explained in a university news release. "We suspected that trauma was damaging the myelin and slowing the brain's ability to transmit information, interfering with patients' capacity to learn," he explained.
Half of the patients had widespread damage to the myelin. They did 14 percent worse on the mental skills tests, and their brain wiring worked three times more slowly than healthy children. The other 16 brain injury patients had nearly intact myelin. Their brains processed information as quickly as healthy children, and they did 9 percent better on the mental skills tests than those with more myelin damage.
The study, published in the July 15 issue of the Journal of Neuroscience, offers possible indicators that doctors could use to identify higher-risk brain injury patients who require closer monitoring, the researchers said.
Traumatic brain injury is the single most common cause of death and disability in American children and teens, according to the U.S. Centers for Disease Control.